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<head><meta charset="utf-8"><title>revert of c unwind abi PR #84672 · t-compiler · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/index.html">t-compiler</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html">revert of c unwind abi PR #84672</a></h3>

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<a name="236742396"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236742396" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236742396">(Apr 29 2021 at 20:47)</a>:</h4>
<p>Hey, so I had thought reverting the PR that introduced the c unwind ABI would be trivial</p>



<a name="236742472"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236742472" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236742472">(Apr 29 2021 at 20:47)</a>:</h4>
<p>but Miri has a dependency on the Abi structure defined in <code>rustc_target</code></p>



<a name="236742612"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236742612" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236742612">(Apr 29 2021 at 20:48)</a>:</h4>
<p>so now I’m debating about whether I should try to coordinate that change (which I guess involves changing Miri upstream submodule?) or if I should take the plunge and backport PR <a href="https://github.com/rust-lang/rust/issues/84158">#84158</a> instead</p>



<a name="236743138"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743138" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743138">(Apr 29 2021 at 20:52)</a>:</h4>
<p>How is this normally handled?</p>



<a name="236743181"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743181" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743181">(Apr 29 2021 at 20:53)</a>:</h4>
<p>/me skims PRs on miri repo</p>



<a name="236743279"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743279" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743279">(Apr 29 2021 at 20:54)</a>:</h4>
<p>hmm</p>



<a name="236743347"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743347" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743347">(Apr 29 2021 at 20:54)</a>:</h4>
<p>I had thought that tool breakage wouln’t block bors merging?</p>



<a name="236743359"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743359" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743359">(Apr 29 2021 at 20:54)</a>:</h4>
<p>it's beta week, at least</p>



<a name="236743370"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743370" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743370">(Apr 29 2021 at 20:54)</a>:</h4>
<p>Oh.</p>



<a name="236743384"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743384" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743384">(Apr 29 2021 at 20:54)</a>:</h4>
<p>on beta channel we shouldn't care about miri I think?</p>



<a name="236743392"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743392" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743392">(Apr 29 2021 at 20:54)</a>:</h4>
<p>So during beta week, we want to make sure tools build</p>



<a name="236743397"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743397" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743397">(Apr 29 2021 at 20:54)</a>:</h4>
<p>is that idea?</p>



<a name="236743411"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743411" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743411">(Apr 29 2021 at 20:54)</a>:</h4>
<p>I guess I knew that. :)</p>



<a name="236743414"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743414" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743414">(Apr 29 2021 at 20:54)</a>:</h4>
<p>right, because otherwise we can't branch off</p>



<a name="236743430"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743430" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743430">(Apr 29 2021 at 20:55)</a>:</h4>
<p>hmm</p>



<a name="236743432"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743432" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743432">(Apr 29 2021 at 20:55)</a>:</h4>
<p>but I don't know if miri is in that set</p>



<a name="236743439"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743439" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743439">(Apr 29 2021 at 20:55)</a>:</h4>
<p>I think it is</p>



<a name="236743477"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743477" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743477">(Apr 29 2021 at 20:55)</a>:</h4>
<p>but you’re saying maybe miri <em>shouldn’t be</em> in that set?</p>



<a name="236743505"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743505" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743505">(Apr 29 2021 at 20:55)</a>:</h4>
<p>right, I think this is hitting <a href="https://github.com/rust-lang/rust/issues/74709">https://github.com/rust-lang/rust/issues/74709</a></p>



<a name="236743524"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743524" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743524">(Apr 29 2021 at 20:55)</a>:</h4>
<p>Ah ha</p>



<a name="236743541"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743541" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743541">(Apr 29 2021 at 20:55)</a>:</h4>
<p>so it might be possible to 'adjust' to just not build miri</p>



<a name="236743542"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743542" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743542">(Apr 29 2021 at 20:55)</a>:</h4>
<p>Okay</p>



<a name="236743595"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743595" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743595">(Apr 29 2021 at 20:56)</a>:</h4>
<p>but imo, rather we should revert via the smaller pr if possible</p>



<a name="236743601"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743601" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743601">(Apr 29 2021 at 20:56)</a>:</h4>
<p>seems easier if it just works</p>



<a name="236743639"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743639" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743639">(Apr 29 2021 at 20:56)</a>:</h4>
<p>As in, just backport PR <a href="https://github.com/rust-lang/rust/issues/84158">#84158</a> instead, right?</p>



<a name="236743648"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743648" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743648">(Apr 29 2021 at 20:56)</a>:</h4>
<p>yeah</p>



<a name="236743650"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743650" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743650">(Apr 29 2021 at 20:56)</a>:</h4>
<p>I think that’s the right call at this point</p>



<a name="236743680"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236743680" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236743680">(Apr 29 2021 at 20:56)</a>:</h4>
<p>scenarios like this are exactly why we approved backporting it if the revert failed. :)</p>



<a name="236747964"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/revert%20of%20c%20unwind%20abi%20PR%20%2384672/near/236747964" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/revert.20of.20c.20unwind.20abi.20PR.20.2384672.html#236747964">(Apr 29 2021 at 21:15)</a>:</h4>
<p>(its unfortunate that PR <a href="https://github.com/rust-lang/rust/issues/84158">#84158</a> does not have a regression test. <span aria-label="sad" class="emoji emoji-2639" role="img" title="sad">:sad:</span> )</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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